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Method for preparing 3,5-difluorophenol

A technology of difluorophenol and trifluoroaniline, which is applied in the field of preparation of 3,5-difluorophenol, can solve problems such as no synthesis reports, and achieve the effects of easy-to-obtain raw materials, high yield, and simple process

Inactive Publication Date: 2018-03-13
上海伟和生物科技有限公司
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  • Abstract
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Problems solved by technology

[0003] 3,5-Difluorophenol is a gray-white crystal with a melting point of 51-55°C. It is mostly used in the synthesis of liquid crystal materials, anti-fungal agents, etc., and is also used in the synthesis of dyes, plastics and rubber additives. It is an important intermediate for medicine, pesticides, and liquid crystal materials. , there is demand in the market, but there is no synthesis report in China, and there are several synthesis methods abroad:

Method used

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  • Method for preparing 3,5-difluorophenol

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Embodiment Construction

[0025] A kind of preparation method of 3,5-difluorophenol of the present invention comprises concrete steps as follows:

[0026] (a) raw material preparation: 3,4,5-trifluoroaniline mass fraction is 99%, concentrated sulfuric acid mass fraction is 98%, hypophosphorous acid mass fraction is 50% aqueous solution, all industrial supplies, sodium nitrite and dichloromethane , chemically pure; sodium nitrite and dichloromethane as catalysts.

[0027] (b) Preparation of diazonium salt: 3,4,5-trifluoroaniline is added dropwise to the reaction bottle A that is equipped with an appropriate amount of mass fraction of 50% sulfuric acid solution, stirring while adding, controlling the reaction temperature below 30°C, when more than half of the amount of 3,4,5-trifluoroaniline is added dropwise, the temperature of the water bath is raised to 55°C to speed up the drop rate; reaction bottle A is made of polyethylene.

[0028] (c) reaction: be cooled to below 20 ℃ after dropwise addition, dr...

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Abstract

The invention discloses a method for preparing 3,5-difluorophenol, wherein the method includes the following specific steps: (a) raw material preparation; (b) diazonium salt preparation: dropwise adding 3,4,5-trifluoroaniline into a sulfuric acid solution with the mass fraction of 50%; (c) reaction; (d) diazonium salt hydrolysis: adding a 50% hypophosphite solution, adding a catalyst, dropwise adding the diazonium salt solution, and stirring; and (e) separation and purification: carrying out extractive rectification, to obtain the target compound. The synthetic route of the designed process isrelatively simple, the raw materials are easy to get, the cost is low, the conditions are mild, and the yield is relatively high; the method is a relatively ideal synthetic method; the target compound is widely used, and is suitable for industrialized production.

Description

【Technical field】 [0001] The invention relates to the technical field of medicine, pesticide and liquid crystal material intermediates, in particular to the technical field of a preparation method of 3,5-difluorophenol. 【Background technique】 [0002] The chemical stability and physiological activity of organic fluorine compounds are significantly higher than other compounds, and they have strong fat solubility and hydrophobicity. It has been verified that fluorine-containing medicines and pesticides are less toxic and more effective than other products in terms of performance. It has high metabolism and stronger metabolism, so it is widely used in the fields of medicine and pesticide manufacturing. In addition, market prospects can also be seen in some other fields, such as the development and application of synthetic fluorine-containing dyes, fluorine-containing surfactants, fabric finishing agents, and coatings. [0003] 3,5-Difluorophenol is a gray-white crystal with a ...

Claims

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Application Information

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IPC IPC(8): C07C37/045C07C37/68C07C37/72C07C37/74C07C39/27
CPCC07C37/045C07C37/685C07C37/72C07C37/74C07C245/20C07C39/27
Inventor 杨遗志
Owner 上海伟和生物科技有限公司
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